Sparse Code Multiple Access (SCMA) and Blind Interference Alignment (BIA) are key enablers for multi-user communication, yet each suffers from distinct limitations: SCMA faces high complexity and limited multiplexing gain, while BIA requires a long temporal channel pattern and incurs significant decoding delay. This paper proposes SBMA (Sparsecode-and-BIA-based Multiple Access), a novel framework that synergizes SCMA's diversity and BIA's multiplexing while addressing their drawbacks. We design two decoders: a low-complexity two-stage decoder (Zero-forcing + Message Passing Algorithm (MPA)) and a Joint MPA (JMPA) decoder leveraging a virtual factor graph for improved BER. Theoretical analysis derives closed-form BER expressions for a 6-user 2x1 MISO system, validated by simulations. Compared to existing schemes, SBMA with JMPA achieves a diversity gain equivalent to STBC-SCMA and a multiplexing gain comparable to BIA, while simultaneously offering enhanced privacy (relative to STBC-SCMA) and reduced reliance on channel coherence time (compared to BIA). These advancements position SBMA as a compelling solution for next-generation wireless communication systems, particularly in IoT applications demanding high throughput, robust data privacy, and adaptability to dynamic channel conditions.

翻译：稀疏码多址接入（SCMA）与盲干扰对齐（BIA）是多用户通信的关键使能技术，但各自存在明显局限：SCMA面临高复杂度与有限复用增益的问题，而BIA需要较长的时域信道模式并产生显著解码延迟。本文提出SBMA（基于稀疏码与BIA的多址接入），这一新颖框架协同融合了SCMA的分集增益与BIA的复用增益，同时克服了二者的缺陷。我们设计了两种解码器：一种低复杂度的两级解码器（迫零+消息传递算法（MPA））以及一种利用虚拟因子图以提升误码率性能的联合MPA（JMPA）解码器。通过理论分析推导了6用户2x1 MISO系统的闭式误码率表达式，并经由仿真验证。与现有方案相比，采用JMPA的SBMA在获得与STBC-SCMA相当的分集增益的同时，实现了与BIA相近的复用增益，并且同步提升了隐私保护能力（相对于STBC-SCMA）并降低了对信道相干时间的依赖（相较于BIA）。这些进展使SBMA成为下一代无线通信系统，尤其是对高吞吐量、强数据隐私及动态信道条件适应性有需求的物联网应用中极具吸引力的解决方案。